Allegheny Ludlum Corporation

Yeong-U Kim

Donald R Zaremski

Lewis L Kish

Nazmi Toker

Richard Kazeva

Carol S Hertzler

Lawrence R Barkowski

Methods are provided for annealing coils of austenitic stainless steels through the use of a batch annealing process. The preferred methods involved selecting compositions of austenitic stainless steel alloys having a sufficiently low weight percentage of carbon so that annealing of the austenitic stainless steel occurs without intergranular carbide precipitation at a temperature of less than about 1700.degree. F., which is well below the normal annealing temperature for austenitic stainless steels. The lower annealing temperatures allow for annealing in conventional batch annealing furnaces. The content of carbon in T-201L stainless steel was kept at less than 0.030 weight percent and the steel was successfully annealed at temperatures within a range of about 1650.degree. F. to about 1700.degree. F. The carbon content of T-304L stainless steel was kept at less than 0.015 weight percent and the steel was successfully annealed at temperatures within a range of about 1550.degree. F. to about 1700.degree. F. For light gauge strip, the winding tension of the coiled stainless steel was reduced prior to the batch annealing process. In particular, winding tensions of less than about 30,000 psi were beneficial, with good results being found when the winding tension was held within the range of about 15,000 psi to about 3,000 psi.

Method for batch annealing of austenitic stainless steels

A method for producing a dual phase ferrite-martensite steel product from a cold rolled stainless steel. The method includes a step of rapidly heating the steel to annealing temperature in less than 30 seconds, followed by a step of cooling the heated steel at a cooling rate sufficient to transform austenite to martensite.

Process for producing dual phase ferritic stainless steel strip

A method for processing stainless steel strip or sheet provides for cleaning the surface of the stainless steel with a solution selected from the group consisting of water and alkaline-based and acid-based compounds to reduce oxide scale formation and to provide more uniform oxide scale during subsequent annealing by transverse-flux induction heating up to an annealing temperature of about 2300 degrees Fahrenheit and then electrolytically descaling by immersing in an aqueous solution electrolyte of one neutral salt, preferably, sodium sulfate maintained at a temperature in excess of 150 degrees Fahrenheit and with the use of low current density of 0.1 to 1.0 amperes per square inch to descale the steel substantially entirely, and thereafter applying a water rinse combined with wet wiping to the electrolytically-descaled stainless steel.

Annealing and descaling method for stainless steel

A method is provided for further processing cold-rolled, stainless-steel sheet or strip by being induction-heated to an annealing temperature in the range of up to 2300 degrees Fahrenheit, causing the formation thereon of a scale of having thickness of less than 2000 Angstroms, followed by electrolytic descaling at high current density in an aqueous solution of 15 to 25 weight percent of sodium sulfate, maintained at a temperature of at least 150 degrees Fahrenheit.

Method for processing cold-rolled stainless-steel sheet and strip

An apparatus and method for quantitatively evaluating the finish of a curved surface of a rolling mill roll or a coil of strip. A light beam is directed by the position of a support housing at a specific incident angle onto the curved surface and a plurality of light detectors are positioned by the support housing above the curved surface for measuring the intensity of reflected light in various directions as defined by the positions of the light detectors. The housing is positioned by stabilizing arms at opposite sides of the housing so that the housing and stabilizing arms form three points of contact with the curved surface. A roller with journals at opposite ends is supported by each stabilizing arm. The longitudinal axes of the rollers are parallel to the longitudinal axis of the roll or coil of strip so that the light beam travels in a plane which is also parallel to longitudinal axis of the roll or coil of strip. An electrical circuit is coupled to the light detectors for calculating the value of specular reflectance as well as reflected light at various angles thereto.

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Export, PA, United States of America

Yeong-U Kim